In many electrochemical processes, especially in galvanic metal deposition, substrates are treated by bringing metal ions to the substrate using an electrolyte stream. Typically, electrical charges are carried by ions in the electrolyte, and the substrate is electrically connected to supply the process with electrons. The chemical, hydraulic and geometrical properties of the electrolyte stream determine the amount of ions that is brought to the substrate and particularly to certain regions of the substrate. In typical processes, the intensity of the treatment is dependent on the amount of ions which reach a certain place on the substrate.
In many electrochemical processes, a homogeneous treatment is required. In order to achieve this, it is desired to bring the same amount of ions to each point of the substrate. Usually, the electrolyte is directed to a substrate using at least one nozzle through which the electrolyte passes. This leads to the higher treatment intensity at the points of the substrate to which the nozzles and thus the electrolyte stream are directed. In case of a galvanic metal deposition process, this leads to greater coating thickness at these points which renders the coating inhomogeneous. Further, the electrolyte stream is not homogeneous. Thus, also from this fact and inhomogeneity arises.
In the state of the art, often the greatest distance possible between the anode and the substrate is chosen in order to homogenize the electrolyte stream over the distance regarding concentration effects caused by at least one nozzle which directs this stream towards the substrate. This delivers usable results which, however, are improvable. To this end, in the state of the art, processes are known in which the substrate is moved relative to the nozzles which is carried out in order to homogenize the treatment of the substrate. These movements are carried out as circular movements of the whole substrate around a fixed point of the substrate.
A disadvantage of this known process is that a still quite inhomogeneous coating thickness results in the region of the fixed point around which the circular movement is carried out.